Some powered systems (such as, but not limited to, automobiles, off-highway vehicles, marine diesel powered propulsion plants, stationary diesel powered system, agricultural vehicles, and other vehicle systems) are powered by one or more power units, such as engines. Some vehicle systems may include multiple vehicles that travel together along a route. The vehicles may be complex systems with numerous subsystems, with each subsystem being interdependent on other subsystems.
More than one propulsion-generating vehicle may be provided in a vehicle system, wherein these vehicles are referred to as a vehicle consist (e.g., the consist is a group of propulsion-generating vehicles that operate together in moving a vehicle system). To function together, the vehicles communicate with each other. The numerous subsystems on the vehicles also may communicate with like subsystems on the other vehicles. As one example, vehicles may be provided in a distributed power (DP) arrangement with one vehicle designated as a lead vehicle and other vehicles designated as remote vehicles. The lead vehicle may direct the tractive and braking efforts provided by the remote vehicles during a trip of the vehicle system.
The information that is communicated between the vehicles can include information such as, but not limited to, braking commands and other braking-related information between vehicles and/or vehicle consists within the same vehicle system. This communication may be done either using wireless communication paths and/or wired communication paths between the vehicles. A wired communication path may pass through other vehicles in the vehicle system (e.g., non-propulsion-generating vehicles, such as trailers, rail cars, or the like) that separate vehicle consists. Communication networks for specific subsystems are usually unique for these specific subsystems. Therefore, if a communication path of a specific subsystem fails, a redundancy path may not be available. Not having an available redundant path may result in the vehicle system losing performance capabilities to an extent of being non-functional.
With respect to wireless communication between the vehicles, the wireless messages can be communicated in a variety of different protocols. These different protocols can dictate the syntax, content, format, or the like, of the information included in the messages. Messages communicated in different protocols may not be understood by different systems. Systems onboard different vehicles may use different protocols and, as a result, these systems may not be able to communicate with each other.
In order to ensure that the vehicles in a vehicle system are able to communicate with each other, the vehicles may need to all be the same type of vehicle and include systems that communicate using the same protocol. Because a wide variety of vehicle types and vehicle systems exist, forming a consist with only a single type of vehicle and vehicle systems that communicate using the same protocol can significantly limit the consists that can be formed.
Communications also may occur between vehicles and other devices, such as an end-of train (EOT) or end of vehicle (EOV) device. One or more of the vehicles may periodically communicate with the EOT or EOV device that monitors one or more characteristics of the vehicle system, such as air brake pressure.
Responsive to a communication loss with the EOT or EOV device, the vehicle system may inform an onboard operator of the vehicle system. This operator may then be required to initiate a check on the communication with the EOT or EOV device and may be instructed to terminate any automatic control of the movement of the vehicle system. The operator may then reduce the moving speed of the vehicle system to or below a reduced speed limit (e.g., relative to a speed limit of the route that was applicable prior to the communication loss).
These operations by the operator require the operator to take his or her attention away from the other operations of the vehicle system. This can result in an unsafe situation, as the vehicle system may initially be traveling at a fast speed.